As halophytes, mangroves are able to live in freshwater and saltwater environments. Photo courtesy U.S. Fish and Wildlife Service

Salinity Levels

Adaptations make it possible for mangroves to live in saline environments

As facultative halophytes, mangroves do not require saltwater to survive. Most mangroves are capable of growing in freshwater habitats, although most do not due to competition from other plants.

Nutrients are transported into mangrove communities by tides. Photo courtesy U.S. Geological Survey

Tidal Fluctuations

Tides bring in nutrients and remove wastes from mangrove communities

Tidal fluctuations play important roles in maintaining mangrove communities. The changing tides, in combination with salinity levels, reduces competition from other plant species. Tides transport salt water into estuaries, mixing with freshwater, thereby allowing mangroves to develop further inland than otherwise possible. Nutrients are transported into mangroves by incoming tides while waste products are removed by outgoing tides. Also of importance is the role tides play in transporting the propagules (seedlings) of mangrove trees. This increases the distribution of the mangrove trees, while limiting intraspecific (within species) competition for food and space.

Glossary terms on page:

tropical: tropical zone lies between 23.5 degrees north and south of the equator, has small seasonal changes in temperature and large seasonal changes in precipitation.

facultative: the ability of an organism to survive either in the presence or absence of an particular environmental factor.

salinity: concentration of total salts dissolved in water, usually measured in parts per thousand.